Method of making composite gears.



No. 814,342. PATENTBD MAR. B, 1906. H. B. A'I'HA.

METHOD 0? MAKING GOMPOSITB GEARS.

APPLIOLTIOI YILBD IQY. 23, 1904 2 SHEETS-SHEET 1.

UNITED STATES PATENT OFFICE.

HERBERT BURR ATHA, OF EAST GRANGE, NEW JERSEY.

METHOD OF MAKING COMPOSITE GEARfS.

Specification of Letters Patent.

Patented March 6, 1906.

application filed November 23, 1904, Serial 110. 288,936.

shape for a much longer time than it is possible to do under the present process of manufacturing gears.

Another object thereof is to provide an efficient and inexpensive gear the outer art of which is removable when desired an yet is securely fixed in position, so as not to become loose ordetached during use.

Another object is to rovide'a' simple art of formin a gear of the a ove t pe.

Anot er object is to provi e a gear of the above t e in which the pitch-line is a true circle arid the shaft is at the center thereof.

Another object is to provide an art pecul- V iarly adapted to the formation of such a gear.

Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists in the several steps and order and reiation one to another of these steps and the features of construction, combinations of elements, and

arrangement of parts, which will be exemplifled hereinafter and the scope of the ap heation of which will be indicated in the c aims at the'end of this description.

In order to render clearer the general nature of my invention, it may be noted that in gears as 'now constructed it is necessary to make them of steel so soft that the gear maybe machined to a finished an i accurate size. My process makes it possible a cast the teeth so accurately that it is pracgicabie to grind to become distorted in cooling an shrinking,

as the parts will cool and shrink unevenly, and the radial arms of the gear will assist this uneven shrinking, thus throwing the itchcircle out of true. Moreover, it may a so be noted that if a gear of the ordinary construction be formed of the grade of metal ordinarily used for such urposes the teeth will wear rapidl and also t ere is more liability of the teeth sing broken off than if the gear were constructed of the metal and in the manner herein described by me.

other defects are remedied in constructions of the nature and made according to the art hereinafter described.

In carrying on my invention 1 cast an outer band provided with ear -teeth of a hi hgrade metal, preferab yof steel so hard that it cannot be machined or milled by a cutting- The teeth thus formed may be spur or 7 tool. bevel or any other desired t-vpeyandit may here be noted that the word gear is used throughout this specification and in the following claims in a broad sense as covering any form of gear or gear-teeth. After the casting has become cool pressure is a plied to the outer surface thereof, so as to orce the same into such sha e that the itch-circle will be ap roximate ytrue. Wit the band held in t 's position the inner surface is ground to a true circle and preferably slightly tapered, the continuance of the external pressure insuring that this inner surface will be exactly concentric with respect to the pitchcircle and that the band will not be distorted by the grinding-tool. After the band 'has been formed asabovedescribed, an accurately-turned core or center, by which latter term it is intended to comprehend any form of mounting for the band, is forced within the same, the external pressure upon the band. being maintained as before. These parts are so proportioned in size and shape as to require a considerable amount of force to drive the center in place, and it has been found that under such circumstances the banduis so securely mounted as not to he- :come loose or detached in use. The-pressure upon the outer surface of the gear is then relieved and the teeth ground accurately to shape. s V

The above and It may be here noted that, if desired, in a.

construction of an annular gear I may form teeth u on the inner surface of the band and force t e member upon which the band IS mounted about instead of within the same.

In the accompanying drawings,in which 18 shown a'gear embodying certain features of my invention, Figure I is a plan of the same. Fig. 2 is a vertical section taken on the line 2 2 of Fi 1. Fig. 3 is a plan view of a chuck for hol ing the outer band of the lgear while the same is being trued up and he d in place during the turning and securing operations. Fig. 4 is a section on line 4 of 3. Fig. 5

1g. 6 is a secis a section on line 5 of Fig. 3. tion on line 6 of Fig. 3.

Similar reference characters refer to similar parts throughout the several views.

In the drawin 1 represents a band formed as above descri ed, having forced therein a center 2, the two contacting surfaces of these parts being smooth, as shown at 3.

The chuck is marked A on the drawings, and the body of the chuck is lettered B.

0 represents screw threaded shafts, as shown in the drawin 3. On the outer ends of these shafts are the beveled pinions D.

E is a circular rack fitted 1n the body B of the chuck and meshing with the inions D.

F is a short shaft mounted in t e main ortion B of the chuck and havin -a pinion on the inner end thereof, which a so meshes with the circular rack E.

The parts lettered H are jaws which have downward] -pro'ecting lugs J, said ,lu s being screw-t ea ed at J, into which fit the screw-threaded shafts C. Upon turning the short shaft F the circular rack will be moved, which meshing with the pinions D will turn the shaft C and move the jaws H toward .or from the center of the chuck, it being understood, of course, that the main portion B of the chuck is slotted, as shown at B, through which the lugs J of the jaws move. All of these jaws move simultaneously, and they can be adjusted to fit against the outer end of the teeth of the band ed e to hold the said band in place while it is eing operated upon;

The chuck disclosed by the new sheet of drawings and this description is an obvious construction, and no claim is laid to it.

This gear 1s used in the'ordinary and obvi ous manner, and no description of its method of use is thought necessary.

It will'thus be seen' that I have provided a simple and eflicient gear in which the teeth may be formed of a highgrade of metal, which is too hard to be dressed, shaped, or milled by a cutting-tool, and the body of comparatively softer materiaLso that the hub may be cut as desired." In this mannerthe advantages above pointed out are attained, and a gear is provided in which the parts subject to severe wear and stresses are abundantly able to resist the same, and yet those parts in which the stresses are less are not formed of such a high grade of material as to render the gear unnecessarily expensive to finish. Also the band, including the teeth, is readily removable upon pressure being applied in the proper manner, and the same ma be replaced in the case of wear or breaking with out waste of the center of the car.

It will also be noted that I ave provided an art for formin a gear of the above type in which the teeth 0% the gear are made of metal of such high qualit and hardness that it is necessary to finish t e teeth by grin and this can be done at a minimum of skil ed labor.

As my invention could be carried on and embodied in apparently widely different manners and forms without departing from the scope thereof I desire that all matter herein set forth shall be interpreted as illustrative and not in a limiting sense.

I desire it also to be understood that the lan uage used in the followi claims is inten ed to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which as a matter of language might be said to fall therebetween.

aving described my invention, what I claim as new, and desire to secure by Letters Patent isl. The art which consists in casting an annular member and integral teeth therewith, holding the member in a circular form,grinding the surface of the member opposite that ulpon which the teeth are cast, and forcing t e same and a member to which it is to be connected into operative position with relation to each other.

2. The art which consists in casting an annular member having integral gear-teeth upon the outer surface thereof,- gnnding the inner surface of said member concentric with the pitch-circle of said gear-teeth, and forcinga center within the same.

3. The art which consists in casting an annular member ha in al gear-teeth upon the outer surface thereof, holding the outer surface of said member in a circular form, grin the inner surface of said member concentric with the pitch-circle of said gear-teeth, and forcing a center within the same.

4. The art which consists in cast' an annular band having inte al gear-teat upon 5. The'art which consists in cestingabend tained durin saigi grinding and during the having integral gear-teeth upon the outer forcing of sei center within said band. to surface thereof, pressing the outer surface of In testimeny whereof I affix my signature said band into a circular form, grindin the in the presence of two witnesses.

inner surface of said band concentriewit the HERBERT BURR ATHA. pitch-circle of said gear-teeth, and forcing a Witnesses:

center within the sa1ne,-said ressure upon H. M. SEAMANS,

the outer surfece of said hens being mein- I F. R. RICHARDS. 

